High Resolution Microwave Spectra of HeN and (H2)N Linear Molecule Clusters Wolfgang Jger Department of Chemistry, University of Alberta, Edmonton, AB Canada Collaborations: Yunjie Xu, UofA Bob McKellar, NRC PN Roy, Nick Blinov, UofA (H2)N Molecule Clusters on this Meeting MH15: H2 C5H5N Chakree Tanjaroon TE02:
(H2)N N2O, N up to 6 Jen Landry TE03: (H2)N OCS, N up to 7 Julie Michaud High Resolution Microwave Spectra of HeN Linear Molecule Clusters Wolfgang Jger Department of Chemistry, University of Alberta, Edmonton, AB Canada Collaborations: Yunjie Xu, UofA Bob McKellar, NRC PN Roy, Nick Blinov, UofA
Impetus for HeN-Molecule Studies He OCS, He HF, etc. studies by Higgins and Klemperer. SF6, OCS Helium nanodroplet studies by the Scoles/Lehmann and Toennies/Vilesov groups. 50th OSU Symposium, Outstanding Challenges for Molecular Spectroscopy (compiled and distilled by Kevin Lehmann) V. Towards a true Microscopic Theory of Condensed Matter e) Improvements in experiments and theory of the size dependence of molecular properties to better understand the transition from an
isolated molecule small cluster condensed phase. A Case in Point: Superfluidity 4He becomes superfluid below the -point (2.17 K). Frictionless flow, irrotationality, quantized vorticity, fountain effect Andronikashvili experiment Drag from normal fluid component causes increase of moment-of-inertia of disk stack. Confirmation of twofluid model. The Microscopic Andronikashvili Experiment Pure 4He droplet Pure 3He droplet
4 He droplet with 20 3He 4 He droplet with 40 3He 4 He droplet with 60 3He 4 He droplet with 1000 3He Grebenev, Toennies, Vilesov, Science 279, 2083 (1998).
Instrument and Technique Alberta: Rotational (microwave) spectra of HeN-molecule clusters. Instrument: FTMW Spectrometer, 2.5 - 11 GHz. Ottawa: Ro-vibrational (infrared) spectra of HeN-molecule clusters. Instrument: Rapid Scan mid-IR Diode Laser spectrometer. Multidimensional Assignment Procedure infrared predictions sample conditions (pressure, temperature) double resonance experiments consistency of isotopic data spectral fits HeN Molecule Clusters HeN-OCS
Effect of Nozzle Cooling on Cluster Formation He6-OCS, J=3-2 at 11176.83 MHz, 0.01% OCS in He at 20.4 atm 100 averaging cycles nozzle at room temperature S/N ~ 2 nozzle at dry ice temperature (-78.5 C) S/N ~ 40 Double Resonance Spectrometer Double Resonance Spectrometer Double Resonance Experiments on He6-OCS pump power
(continuous) off signal: J-3-2, 11176.83 MHz pump: J=2-1, 7588.75 MHz 20 averaging cycles -3 dBm 3 dBm Double resonance experiments also with the decoherence technique. Brendel, Mder, OSU Symposium 2004, paper TA05. Vibrational Frequency Shifts of HeN-OCS Clusters experimental values,
Tang et al., Science 297, 2030 (2002). Paesani, Whaley, JCP 121, 4180 (2004). values from Whaley and co-workers, JCP 115, 10225 (2001). Vibrational Frequency Shifts of HeN-OCS Clusters experimental values, Tang et al., Science 297, 2030 (2002). values from Whaley and co-workers, JCP 115, 10225 (2001). Moment-of-Inertia Shifts of Isotopomers I / amu2
48.8 35.7 37.4 32.1 32.2 Proposed Structure of He8-OCS Helium density in He8-OCS P. N. Roy, N. Blinov, private communication. Spectroscopic Constants of HeN-OCS Clusters Molecule B / MHz
Free OCS D / MHz 6081.59 1.31x10-5 13208.57 5504.18 3661.42 4582.80 0.950 5803.39
4546.34 3019.28 3782.81 --- He3-OCS 3104.57 5.11 He4-OCS 2591.95 0.881
He5-OCS 2225.15 0.234 He6-OCS 1910.49 2.60 He7-OCS 1682.98 1.29
He8-OCS 1447.73 2.00 He-OCS He2-OCS OCS in 4He droplet (N~3,000) 2194.5(90) 11.4(3)
Rotational Constant vs.Number of He Atoms Quantum Monte Carlo Calculations. N. Blinov, X. Song, P. N. Roy, JCP 120, 5916 (2004). S. Moroni et al., Phys. Rev. Lett. 90, 143401 (2003). Helium Density Profiles in HeN-OCS N=5 N=6 N=7 N=8 N=9
N=10 N. Blinov, X. Song, P. N. Roy, JCP 120, 5916 (2004). HeN Molecule Clusters HeN-N2O He6-N2O in its Principal Inertial Axes System J=1-0 Rotational Transition Intensity He5-14N15NO 6792.0 6793.5
Intensity He7-14N15NO 5471.5 5473.0 Intensity He12-14N15NO 6194.5 6195.5 Frequency / MHz Rotational Constant vs.Number of He Atoms
Helium droplet value Nauta, Miller, JCP 115, 10254 (2001). Xu, Jger, Tang, McKellar, Phys. Rev. Lett. 91, 163401 (2003). S. Moroni, N. Blinov, P. N. Roy, J. Chem. Phys 121, 3577 (2004). Xu, Jger, Blinov, Roy, J. Chem. Phys. 124, 081101 (2006). Helium Density Distributions in HeN-N2O N=5 N=6 N=9 N=10 N=14
N=15 HeN Molecule Clusters Back to HeN-OCS Infrared Spectra of HeN-OCS Clusters Bob McKellar, paper FD01 R(0) Transitions 70 20 50 60 18 40
17 16 30 15 14 2062.0 2062.1 2062.2 Wavenumber / cm-1 2062.3
J=1-0 MW Transitions of HeN-OCS Clusters 6e+8 4e+8 Nanodroplet value 3e+8 um 30 of he li
0 6000 3000 0 nu m 10 N, Fre que 4000
ncy / MH z be r 20 5000 J=1-0 2B m 40 1e+8
s 50 2e+8 at o de Amplitu 5e+8 400 k Hz
J=1-0 MW Transitions of HeN-OCS Clusters Rudi Lehnig, RD05 6e+8 4e+8 3e+8 um 30 of he li 0 6000 5000
m 10 3000 0 nu Fre que 4000 ncy / MH z be r
20 m at o 40 1e+8 s 50 7000 2e+8
N, de Amplitu 5e+8 J=1-0 MW Transitions of HeN-OCS Clusters Rudi Lehnig, RD05 6e+8 4e+8 3e+8 um 30
of he li 0 6000 5000 m 10 3000 0 nu
Fre que 4000 ncy / MH z be r 20 m at o 40
1e+8 s 50 7000 2e+8 N, de Amplitu 5e+8 Rotational Constant B as Function of Cluster Size
Rotational constant, B" / MHz 3000 S. Paolini et al., JCP 123, 114306 (2005). S. Moroni et al., PRL 90, 143401 (2003). 2500 Whaley and coworkers, PRL 90, 073401 (2003); JCP 121, 4180 (2004); JCP 123, 114301 (2005). 2000 1500
nanodroplet * B-value Toennies, Vilesov, and co-workers JCP 112, 4485 (2000) Experiment 0 10 20 30 40 50 Number of helium atoms, N
60 70 Rotational Constant B as Function of Cluster Size Rotational constant, B" / MHz 3000 S. Paolini et al., JCP 123, 114306 (2005). S. Moroni et al., PRL 90, 143401 (2003). 2500 Whaley and coworkers, PRL 90, 073401 (2003);
JCP 121, 4180 (2004); JCP 123, 114301 (2005). 2000 1500 nanodroplet * B-value Toennies, Vilesov, and co-workers JCP 112, 4485 (2000) Experiment 0 10
20 30 40 50 Number of helium atoms, N 60 70 Aufbau of a Helium Solvation Shell Structure Acknowledgements
Dr. Dominik Bremm Dr. Rudi Lehnig (RD05) Dr. Chakree Tanjaroon (MH15) Jen Landry (TE02) Julie Michaud (TE03) Wendy Topic Qing Wen (TE05) NSERC, CFI, ASRIP, University of Alberta, CRC
